Container body



R. G. ATKINSON Feb. 22, 1944.

CONTAINER BODY Filed March 24. 1942 INVENTOR.

ATTORNEYS y `Patented Feb. 22, 1944 i. 21.! costume sony lr i I Reid dntkinsmi, nonovlu'lu, Territori of-namlif I as s'ignor to American Can Company', New York,

N. Y., a corporation 'of'New-Jersey y I Application 'Maren 24, 1942,' 'serial No; 436,039

(crm-) .3 Claims. The invention relates to sheet metal .cans or containers adapted to be vacuumized and has particular reference to a lapped end portionof the lock and lap vside vseamro'f a can body in which the laps are secured` by solder andby an electric weld disposed in a' predetermined locationwhich controls the quantity of solder-A applied to the joint to maintainthe latter vacuum tight after th'el body .h asbeen' assembled with an end to form a can. Thisis an improve ment overUnited States Patent-1,542,662', is`

sued June 16, 1925, to Julius Brenzinger.: 1

In the manufacturek of .can bodies which are adapted for certain uses andwhichhave ,lock and lap side seams it has been the practice to spot weld the lapv portions ofv the seam tois large enough to establish an opening throughA the joint from the outside of the can to its in.

terior. This channel as a rule is very small but is sufficient to permit of .a slow leak which destroys the vacuum in the can and results in spoilage of its contents. In cans not vacuumi'zed, as in the Brenzinger patent mentioned above, the interior and exterior pressures are more nearly equal, therefore there is not the same tendency for air to enter through the small channel.

Furthermore it has been found that the weld spot often permits only a very thin layer (approximatelyv 0.001 inch) of solder to enter between the laps and this when cooled becomes brittle. Hence when the body is bent to form between them.

ation to permit the solder to' ow into place The instant invention contemplates overcoming these difcu'lties by making the weld spot of an elliptical shape and of as small an area as possible: and by locating it in a predetermined position at an outer edge ofthe laps so that its holding eiect will be just sufficient to keep the laps together at one point'while allowing a predetermined quantity of solder to enter between the laps `-throughout the entire remaining area lof the joint so that it will be completely sealed.

' By clipping the corner edges of the lapped portions of the body the proper location of the weld spot is facilitated. For be'stvresults it is desirable to locate the spot weld inwardly of the body edge to prevent extruding ofthe metal which v body while Aextrusion forms burrs that cut through the end seams and form leaks. It is also desirable to locate the weld outwardly of the ange bend so that the weld will be free of the bend.

An object of the invention is the provision of a can body having a lock and lap side seam with lap portions having angularly clipped corners forming an apex near the outer edge of the body and which are spot welded at the apex to secure such lapped sections together in a predetermined vrelation so that molten solder in a layer of predetermined thickness may be ilowed therebetween and thus produce a hermetic joint which Another bbject of the invention is the provision of such a can body having spot welded lapped portions that are sealed with a layer of solder of a thickness sufficient to produce a malleable or pliant connection between the laps and which will permit bending of onelap upon the other during the flanging and seaming of the can maintaining a hermetic leak-proof joint.

Numerous other objects'and advantages of the invention will be apparent as it is better underthe usual flanges and end seams, the solder bond is broken and this in effect produces a condition similar to the' channel above mentioned.

It has been determined that when a layer of solder approximately three one thousandths of an inch thick is interposed between the laps, the body of solder is malleable or pliant enough to permit of bending the joint without cracking or breaking the solder. In order to obtain this desired layer of solder the laps must be held apart the proper distance during the soldering operstood from the following "description, which, taken in connection with the accompanying drawing, discloses a preferred embodiment there- Referring-to the drawing:

Figure l is a plan view of a body blank from which a can body embodying the present invention is adapted to be made, with a portion of the blank broken away;

Fig. 3 is a fragmentary view similar to Fig. 2

and showing the same side seam edges after being formed into the body side seam;

Figs. 4 and 5 are sectional views taken along the lines 4 4, 5-5 in Fig. 3, with parts broken away;

Fig. 6 is a side elevation of a flanged can body made from the blank shown in Fig. 1; and

Fig. 7 is an enlarged sectional view taken sub-` stantially along the line 1-1 in Fig. 6.

As a preferred embodiment of the instant invention the drawing illustrates a sheet metal can body A (Fig. 6)'having a conventional lock and lap side seam B. Such a can body is made preferably from a ilat blank C (Fig. 1) having side seam edges I I, I2 formed with respective notches I3 and slits I4 in the usual manner. These notches and slits set oi along a major portion of each seamedge a. folded hook or lock section I6 and a pair of lap sections Il located one adjacent each terminal end. of the lock section (see also Fig. 2).

The lap sections I1 along the seam edge II preferably are cut back or clipped along an angular line of severance so that this clipped edge will be spaced inwardly of the outer edge of the blank. The drawing shows this clipped edge being formed by two angularly disposed intersecting edges I8, I9 which provide a corner or apex 2| spaced inwardly from both adjacent edges of the blank.

When the blank C is formed into tubular can body shape its side seam edges I I, I2 are brought together and are secured in the usual manner by an interlocking of the hook sections I6. It is this interlocking of the edges that produces the lock portion of the seam. The lap sections I1 merely overlap each other as unseamed portions as best shown in Fig. 3 with the clipped lap section disposed on the outside of the body.

The lap or unseamed sections I1 are secured together by an electric spot weld 23. This weld is preferably located at the corner or apex 2I. The weld spot preferably is made relatively small in area and of substantially elliptical shape so that it extends along the clipped edges IB, I9 of the outer lap section and spreads over the edge of the outer lap and onto the under lap. In this position of the weld it is spaced inwardly of the peripheral edge of the can body so that the metal of the body is prevented from being extruded beyond the body edge. This position -'of the weld also tacks down only the outer edge of the outer lap I1 and thus holds this lap lightly so it will spring away from the inner lap and provide a predetermined space therebetween.

It may be mentioned that the desired small elliptical weld spot may be produced by the use of properly spaced electrodes and by the relative positioning of the two electrodes.

The can under consideration is particularly adapted for vacuumized products and for this reason the entire side seam is soldered in order to make the joint hermetic. Some of this solder flows into the space between the inner and outer laps I1 and it is this solder that bonds the laps together and that seals the joint up to the weld as hereinbefore mentioned.

Due to the location of the spot weld the space between the laps I1 is just suflicient to admit a layer of solder that extends over the entire lapped area and which is of a thickness sufficient to impart malleable or pliant properties to the solder so that when the body is bent during the anging and end seamlng operations the bending strains on Vthe solder take place throughout its thickness and not\ on its surface where it, is bonded to the laps of the body. It is this proper thickness of solder that maintains its continuity during the bending operations and which maintains the seal and leak-prooi characteristics of the joint.

It is thought that the invention and many o its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be mad'ein the form, construction and arrangement ci the parts without departing from the spirit and scope of lthe invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A tubular body for a can adapted to be vacuumized, said boch! having a side seam extending the major intermediate portion of its length and having unseamed portions at its opposite ends formed by overlapping edges, the outer of said unseamed portions at each end of said body having an angularly clipped corner spaced inwardly from the end of the body, and a spot weld of relatively small area substantially straddling the apex of said corner for holdim said unseamed portions together in predetermined spaced relation, the space between said overlapped unseamed portions being filled and sealed with solder of suicient thickness and area to provide a hermetic pliant bond so that the body may be hanged and seamed without affecting the hermetic character of the joint.

2. A tubular can body having a side seam extending the major intermediate -portion of its length and having unseamed portions at its opposite ends formed by overlapping edges, the outer of said unseamed portions at each end 0f said body having an angularly clipped corner spaced inwardly from the end of the body, and an elliptical spot weld straddling the apex of said clipped corner and .extending partially along said clipped edges and covering a relatively small area in said unseamed portions for holding such portions together in predetermined spaced relation, said side seam being filled and sealed with solder throughout its length, the solder between the overlapped unseamed portions adjacent the weld being of sufficient thickness and area. to provide a hermetic pliant bond so that the body may be flanged and seamed without detracting from the hermetic character of the joint.

3. A can body having a side seam extending for the major intermediate portion of its length and having unseamed portions at its opposite ends formed by overlapping edges, the outer of said unseamed portions at each end of said body having an angularly clipped corner formed by the intersection of two angular edges providing an apex spaced inwardly from the end of the body, an elliptical spot weld straddling said apex :inwardly of the adjacent can end and extending partially along the two clipped edges to cover a. relatively small area in said unseamed portions for holding such portions together in predetermined spaced relation, said side seam being lled and sealed with, solder throughout its length, the solder between the lapped unseamed portions adjacent the weld being of suilicient thickness and area to provide a hermetic pliant bond so that the body may be hanged and seamed while maintaining the hermetic character of its joint.`

REID G. ATKINSON. 

